A living will and a last will and testament are two completely different types of documents that are used for entirely different purposes. Both are intended to provide instructions for situations during which you are unable to communicate, but having one does not mean you don't need the other. A living will is exclusively focused on health care decisions while you are alive. A last will expresses your preferences after you have died.
A major difference between a will and a living will is the time they take effect. A will has no legal impact until after you're dead, at which time it must be filed with a probate court. A living will, on the other hand, takes effect while you are still alive. Generally, a living will does not go into effect until you are incapacitated, often because you're in a coma or vegetative state in which you are incapable of communicating. Law for Seniors recommends a living will as a useful way to avoid costly and time-consuming litigation among family members about your end-of-life treatment.
Both a will and a living will can nominate an individual to make decisions and take action on your behalf. A will should name an executor, who will inventory your estate, pay your obligations and distribute the residue amongst your beneficiaries. However, the probate court has the final word on who is appointed executor. A living will can appoint someone as your healthcare agent, who can make decisions about your medical treatment. The healthcare agent does not have get prior approval from a court. Some states allow your healthcare representative to donate your body or organs, or to make arrangements for your burial, tasks that must usually be resolved before an executor for your estate is appointed.
The essential function of a living will is to provide instructions to your health care providers and express your preferences for treatment, which is why in some states it is referred to as an advanced healthcare directive. An advanced directive can signal whether you want to receive all possible life support treatment, including artificial respiration and intravenous feeding. Similarly, your living will can reflect the fact that you do not want to receive life support. You can also express preferences for or against other specific treatments and medical procedures.
A last will and testament also expresses your preferences about the disposition of your personal and real property and other assets. You can also use a will to appoint a guardian for your minor children or disabled family members. The directions expressed in your will can only be carried out to the extent any property remains after your debts are satisfied. Assets held jointly or for which a beneficiary is associated, such as a retirement account or life insurance policy, are not subject to probate and are not controlled by a will.